A New Prognostic Score Supporting Treatment Allocation for Multimodality Therapy for Malignant Pleural Mesothelioma: A Review of 12 Years' Experience

Abstract

Treatment of malignant pleural mesothelioma (MPM) remains a clinical challenge. The aim of this study was to identify selection factors for allocation of MPM patients to multimodal therapy based on survival data from 12 years of experience. Eligible patients had MPM of all histological subtypes with clinical stage T1-3 N0-2 M0. Induction chemotherapy consisted of cisplatin/gemcitabine (cis/gem) or cisplatin/pemetrexed (cis/pem), followed by extrapleural pneumonectomy (EPP). Multivariate analysis was performed to assess independent prognosticators for overall survival (OS). A Multimodality Prognostic Score was developed based on clinical variables available before surgery. From May 1999 to August 2011, 186 MPM patients were intended to be treated with induction chemotherapy followed by EPP. Hematologic toxicity was significantly less frequent after cis/pem compared to cis/gem, but there was no difference in response or OS between the regimens. One hundred and twenty-eight patients underwent EPP with a 30-day mortality of 4.7%. Fifty-two percent of the patients received adjuvant radiotherapy. The median OS of patients undergoing EPP was significantly longer with 22 months (95% confidence interval: 20-24) when compared to 11 months (9-12) for patients treated without EPP. A prognostic score was defined considering tumor volume, histology, C-reactive protein level, and response to chemotherapy that identified patient groups not benefitting from multimodality treatment which was confirmed in an independent cohort. Patients receiving induction chemotherapy followed by EPP for MPM of all histological subtypes and irrespective of nodal status showed a median survival of 22 months. A prognostic score is proposed to help patient allocation for surgery after validation in an independent cohort.